Okay since i started the discussion by disagreeing with douglas13 and only translated a small part of the discussion on mi-fo.de i think i should explain some things.
In 2010 Stephan Kölliker aka stevemark wrote \"Das Sony Alpha Vollformat-System\", which is an extensive book about the Alpha-Fullframe-System. He got some financial support from Sony and as it seems also some direct contacts to Sony\'s lens designers.
Based on the contact with these guys he claims this (direct link): \"Die Zeiss ZA-Optiken werden von Sony gerechnet, allerdings nach Kriterien von Zeiss. Interessant ist, dass die Konstrukteure - die eigentlich wissen müssen, was sie rechnen - den eigenen \"G\"-Standard als besser als die Zeiss-Vorgaben betrachten. Sony-Zeiss-Optiken werden nicht in einem einzigen Werk gebaut, sondern teils in Sony-eigenen Werken und teils ausgelagert (ich spreche da von den Vollformat-Optiken; dass etwas dubiose ZA 16-80mm sei mal aussen vor gelasssen). Zudem ist aus den Objektiv-Querschnitten z. B. des MinAF 3.5/17-35mm G (Minolta), des MinAF 2.8-4/17-35mm D (Tamron) und des Sony-Zeiss ZA 2.8/16-35mm eine enge Verwandtschaft der Konstruktionen ersichtlich - was die Aussagen von D. Klipatrick natürlich stützt.\"
my attempt of fixing the google translation: \"The Zeiss ZA-optics are calculated by Sony, but after criteria from Zeiss. Interestingly, the designers - who actually need to know what they do - regard their own \"G\" standard as better than the Zeiss specifications. Sony Zeiss optics are not built in a single work, but partly in Sony\'s plants and partly outsourced (I speak here of the full-frame optics, disregarding that somewhat dubious ZA 16-80mm ). In addition, from the cross-sections of eg. the MinAF 3.5/17-35mm G (Minolta), the MinAF 2.8-4/17-35mm D (Tamron) and the Sony Zeiss ZA 2.8/16-35mm you can see a close relationship between the constructions - naturally this supports D. Klipatricks statement.
mathhiaspaul stays sceptic about stevemarks claims for most of the discussion and is only convinced when some Zeiss guy at photokina basicly confirms what stevemark said earlier: direct link \"Zeiss hat mir, auf dieses Thema angesprochen, auf der photokina explizit gesagt, daß die ZA-Objektive von Sony entwickelt und durch Sony in Japan produziert werden. Zeiss\' Anteil in dieser Kooperation ist es, die Einhaltung bestimmter von Zeiss vorgegebener Kriterien zu überprüfen, bevor ein Sony-Objektiv das Zeiss-Label tragen darf. \"
my translation: \"When i asked them at photokina, Zeiss explicedly told me that the ZA lenses are developed by Sony and produced by Sony in Japan. Zeiss\' share in this co-operation is to verify compliance with certain criteria specified by Zeiss, before a Sony lens may carry the Zeiss label.\"
